Synchros and resolvers, as well known in the art, are rotating devices which provide angular information used in computer systems. These devices generate alternating current analog signals representing the sine and cosine of an angle. The synchro transformer comprises a wye shaped primary winding or stator and a moveable single secondary winding or rotor. The angular displacement between the primary and secondary windings of the synchro transformer provides alternating current analog output signals whose amplitudes represent the sine and cosine of the angles between the primary and the secondary windings.
Tracking synchro to digital techniques usually involve tradeoffs between component count, cost and accuracy. For example, multispeed devices while effective in achieving higher accuracy require more than one sensor and expensive associated gearing mechanism. Additional interface wires and a greater number of electronic parts required to prevent ambiguities in conversion by multi speed devices are also disadvantages. Another example is precision solid state converters which have inherent accuracy that is achieved at great cost and large volume. The desired result is to achieve high accuracy with minimum cost and component count.
The purpose of this invention is to provide means for substantial enhancement of precision in converting from synchro to digital form utilizing fewer discrete parts than required by conventional means by utilizing a novel error compensating technique. This technique enables structure of a compact, low cost converter with accuracy better than two arc minutes. It is understood that the error compensating technique disclosed herein is applicable to the analog to digital converters generally and is not limited solely to synchro to digital converters.